Apparatus for separating particulate materials



Nov. 14,` 1944.1 Y M.; HAwQR'VrH `2f362,48)2` `Arrnuvrus"von` summa-ING PARTICULATE MATERIALS Filed Sept. 21, 1959 5 Sheets-Sheet 1 which the lighter density particles float.

. bottom of the cone.

I Patented Nov. 1 4, .1944" I 'I APPARATUS Fon SEPARATING manovrare MATERIALS Mack E. Haworth, Pittsburgh, Fa. Applieaupp september 21, 1939; serial No. 295,9@

(ci. zas-'iw This invention relates to apparatus for sepa- 4 Claims.

rating or cleaning particulatematerials in which light' and heavy density particles are mixed together, and more particularly to such separation by a heavy density fluid process. For the purpose of illustration only, raw coal, by which is impurities or foreign matter encountered in mining, such as bone coal, shale and pyrites, will be used as an example of such particulate material In heavy density fluid processes the particulate material is -fed to a heavy density fluid through which the heavier density particles sink and on The heavy density particles are drawn off at the bottom of the iiuid and the lighter density particles at the top. An example of this is found in the coal cleaning industry in which the coal, that -is of lighter density than practically any of the refuse with which it comes from the mine, oats on a heavy density iiuid in a cone-shaped hopper from which it is carried away by a light density fluid, such as water, .that continuously circulates in which the density of the fiuid can be accurately and readily determined at any moment:

The preferred embodiment of the invention is illustrated in the accompanying drawings in meant a mixture of pure coal, and heavy density up through the cone. The heavier density particles, which is the refuse that it is desired to separate from the coal, sinks down through the heavy density fluid and into a chamber at the This chamber is provided with upper and lower gate valves, the lower one beingclosed and the upper onebeing open to permit the chamber to receive the refuse or sinks, and the upper one being closed to hold the fluid in the cone when it is desired to lremove a batch of refuse by opening thelower valve.

It will thus be seen that in such apparatus the in batches. Furthermore, every time the upper valve is opened after the chamber below it has been emptied, the heavy density uid in the cone is disturbed and temporarily altered in character so that clean-cut separation can not occur at all times. Another disadvantage of this type of apparatus is that no way has yet been found to satisfactorily and continuously determine the density of the fluid in the cone so that the density may be maintained. substantially constant. As a result, coal oftenpasses out with the refuse or refuse passes off withthe coal, giving either uneconomical separation or dirty coal.

lt is among the objects of this invention to refuse can be removed only periodically and only l which Fig. 1 is a plan view of my apparatus;

Fig. 2 is a side view thereof; Fig. 3 is a view taken I onthe line III-III of Fig. 2; and Fig. 4 is a fragmentary view on a reduced scale of a modication of this invention.

Referring to the drawings, .a generally coneshaped hopper is provided at one side of its upper portion with an opening to which sand return box 2 is connected and at its opposite side vwith another `opening from which an overflow spout 3 extends downwardly. Encircling the cone at vertically spaced intervals are a plurality of tubular rings or manifolds l from which nozzles 6 extend through the wall of the cone at circumferentially spaced points and project downwardly therein. Each ring is connected by a pipe I to a header 8 to which water is supplied through a pipe 9. Sand vof a gravity and in an amount suitable for producing the desired heavy density uid is introduced into the cone where it is thoroughly mixed with the water by the circulation of the water upwardly toward overflow spout 3, and also by mechanical agitation. The later may take the form of agitating blades Il mounted on a vertical shaft l2 rotated by an electric motor I3 mounted above the cone (Fig. 3).

Raw coal or other particulate material is fed in'to the top of the conein any suitable manner,

and the foreign material or refuse, which is of heavier density than the coal, sinks down through the heavy density fluid. The coal litself floats submerged, partly in a body of water that maintains itself on top of the heavy density fluid and partly in the heavy density fluid, and flows out of the cone with that water and as much of the heavy density uid 'as it contained in-the interstices between the coal particles submerged in the uid. The flow from the cone is through spout 3 and onto a a dewatering screen I6 which is hung on rocker arms I1 and is oscillated by a crank I8 (Fig. 2). The water, coal particles, and the sand that is carried out of the cone by the water pass through this screen to a second provide heavy density. uid apparatus in which the sinks can be removed continuously from the hopper, in which the character of the heavy density uid is not disturbed periodically, and

wider'screen I9 below it which is mounted and oscillated in thesa manner. This lower screen veyor or chute, not shown. The waterand sand from the lower screen pass into a tray 2| that has a drain tube 22 extending down into a conical sand sump 23. The water flows upwardly from the tube and leaves the' sand in the bottom of the sump from which it is returned by a pump 24 and pipes 28y and 21 to the box 2 that is connectedto the top of the cone.' To decrease the rate of ilow of water out of the sand sump as much as possible so that it will not carry sand out with it. the upper portion of the sump is provided interiorly with an annular partition 2l provided at circumferentially spaced intervals with openings 29 (Fig. 2) from which trough-like weirs 3| extend radially inwardly to tube 22. The water in the sump flows over the tops of these weirs and flows out through them to and through openings 29 iny the partition. From there the water passes downwardly through openings 32 in the sump and into a tank 33 eny circling the sump. 'This tank is connected by a pipe 34 to pump 3B that returns the water through pipe 9 to header 8. As' the total length of the Weir over which the water in the sump must iiow to escape therefrom is equal to twice the combined length of all the weirs 3|, it will be seen that the water will rise very slowly in the lsump and thereby deposit practically all of its sand therein. A f

Another feature of this invention is that the re- `jects that settle down through the heavy density fluid in the cone may be removed continuously from the bottom of the cone instead of in batches as heretofore. Accordingly, the lower end of the cone is always open and empties into the top of a chamber 4| at the opposite ends of which are vertical conduits 42 and 43 connected together at their tops by a horizontal conduit 44. As shown in Fig. 3, the vertical conduits are tall enough to receive a high enough column of water to balance the heavy density iiuid in the cone, thereby serving as stand-pipes. To prevent the heavy density fluid from settling out oi the cone and down through the water in chamber 4|, whereupon the water in that chamber would ilse into the cone, water is continuously circulated upy wardly through the cone from its bottom.. For

this purpose a pipe 46 leading from header 8` is connected to the top'of the chamber. The water issuing from this pipe not only keeps the necessary amount of water in the chamber and'verti cal conduits, but also ilows up into the cone, and. in effect, supports the heavy density fluid on the lighter density water.

This shaft projects lfrom the side of the chamber 4| and is connected by a lever 56 to a crank 5'! driven by a motor 58 (Fig. 3). llhe gate pushes the sinks off first one end and then the other of the concave plate.

The construction of this apparatus is such that during operation, or when the apparatus is shut down, or when operation is again started, the flow ofwater is always into and up through the cone. Water can not flow from the cone into chamber 4 the flow always -being from the cham- -ber into the cone. Consequently, sandcan not be inadvertently discharged from the cone into the elevator, and mishaps that occur with other apparatus when both operating gates are opened simultaneously are thus avoided.

The sinks that are carried bythe buckets to the upper horizontal conduit 44 are dumped into a chute 6| that extends down to one side of upper screen I6 which is separated by a partition 62 (Fig. l) from the remainder of the screen. The lower screen I9 is likewise divided intov sections by a partition 63. Consequently, the water and small amounts of sand that are carried up by the buckets are screened out and allowed to re turn to the sand sump, while the rejects pass on to a conveyor or the like by which they are removed from the screens. i

A still further important feature of this invention is that the density of the fluid in the con@ can be ascertained at any time by merely looking at a gauge. The height of the column of water in the vertical conduits depends upon the density of the fluid in the cone. The greater the density of that fluid the greater the height of the column of water that is required to balance it. 'Ihe -vertical conduits therefore serve as standpipes, and by connecting a properly calibrated gauge glass 66 or other similar" indicator to the side of one of them the height of the water column therein, and consequently the density of the fluid in the cone, can be determined.. It is preferred to connectthe gauge glass to conduit 43 in which the buckets are moving downwardly, because in the opposite conduit there may be a small amount of sand that is carried up'bythe buckets and To continuously remove the rejects from chamn ber 4| into which they fall from the cone, an endless chin 41 carrying buckets 48 extends through the chamber and connecting conduits through which it travels around sprockets 49 driven continuously by any suitable means. The sand and A other particulate material in the heavy density fluid is prevented from dropping into chamber back into thecone. During normal operational the apparatus the sinks vthat settle onto plate 5| 'are removed therefrom and allowed to fall around the buckets by an oscillating gate 53 mounted on a shaft 54 Journaled in side plates 4| and fouling the buckets, when the, apparatus fis shut down, by means of, a concave plate 5| escapes therefrom. This sand twill increase the density slightly of the column of water in conduit 42,`but the water in the other conduit should be practically free of sand and is therefore a reliable gauge. If desired, the gauge may be connected with means for automatically feeding more sand to the cone whenever the gauge shows that may be attached to a stand-pipe 61 connected to the top of chamber 4|, as shown in Fig. 4. The water in the stand-pipe will rise to the"level required to balance the nula mixture in the cone,

and since the water in the stand-pipe can not con- 4vtain sand in suspension, the level of that water will be a true indication of the specinc gravity of the iiuid mixture in the cone.

Instead of the gauge glass, a .pressure gaugeor other appropriate device may be attached to the elevator casing conduits 42 or 43er to the standpipe, which will indicate the hydraulic pressure at the .base of the cone 'or at other convenient levels and thereby indicate the specific gravity of the fluid mixture in the cone above the level at which the stand-pipe is attached.

Where it is desired to attach a gauge to existing apparatus not fitted with an elevator arrange ment as described above, the stand-pipe may be necting the upper enas or said upright conduits attached to agitating water pipes similar to pipes 1, and by observing the elevation of the pipe relative to the overflow level of the weir, the gauge may be calibrated.

According to the provisions of the patent statutes, I have explained the principle and mode of operation of my invention and have illustrated and described what I` now consider to represent its best embodiments. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

l. Heavy density fluid `flotation apparatus for separating the sinks from the floats of particuchamber and conduit being adapted to contain a high enough level of a light density iluid" to balance the uid in the hopper, means for continuously circulating a light 'density uid up through the hopper to maintain the heavy density fluid therein, and means for removing said sinks from said chamber up through said conduit.

2. Heavy .density fluid flotation apparatus for separating the sinks'from the iloats of particulate materials, comprising a conical hopper for a heavy density fluid and having a downwardly facing opening in its bottom for the substantially unimpeded fall of sinks from particulate material in the hopper, a chamber below said hopper opening for receiving the sinks therefrom, a, concave plate disposed in said chamber below said opening in the path of the falling sinks, means for periodically pushing the sinks over the edge of said 4plate, an upright conduit extending upwardly and provided with an outlet in its bottom, an endless conveyor traveling through said chamber and conduits and including buckets for carrying said sinks up through one of said conduits and discharging them through said outlet, said chamber and first-mentioned conduits being adapted to contain a high enough level of a light density fluid Vto balance the iiuid in the hopper, and means for continuously circulating a light density Vfluid up through the hopper to maintain the late materials, comprising a-hopper for. a heavy heavy vdensity fluid therein.

3. Heavy density nuid flotation apparatus for separating the sinks from the floats of particulate materials, comprising a hopper for a heavy density iiuid and having a downwardly facing open-l ing in its bottom for the substantially unimpeded fall of sinks from particulate materialin the hopper,'a chamber below said hopper opening lfor receiving the sinks therefrom, a plate disposed in said chamber between said opening and the bottom of the chamber in the path of the falling sinks, means for removing sinks from the plate, a conduit extending upwardly from said chamber, said chamber and conduit being adapted to contain a high enough level of a light density fluid to balance the fluid in the hopper, means forcontinuously circuiting-.a light density iluid up through the hopper to maintain the heavy density fluid therein, and means for removing said sinks from said chamber up through said conduit.

4. Heavy density iluid flotation apparatus for separating .the sinks from the floats of particulate materials, comprising an endless conduit' I having laterally spaced upright side portions and vertically spaced top and bottom portions, an endless conveyor traveling in said conduit, the top of said lower portion being provided with an opening, a hopper in the general form of an inverted cone surrounded by said conduit and having'an opening in its lower end communicating with said conduit opening, means for supplying water to said conduit and for circulating it up through said hopper, means for delivering sand to ,the hopper to create a heavy density fluid therein, the bottom of said upper portion of the conduit being provided with an outlet opening, and a chute extending downwardly away from said outlet opening.

MACK E. HAWORTH. 

